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This contribution reviews the newly revised biostratigraphy of Middle–Upper Ordovician marine shelf successions from the Junee–Narromine Volcanic Belt in central New South Wales, based on conodont studies from four areas covering the northern, central and southern sectors of the Belt. Seven conodont biozones ranging from the middle Darriwilian (Histiodella holodentata-Eoplacognathus pseudoplanus Biozone) to the lower Katian (Taoqupognathus blandus Biozone) are recognized in the Billabong Creek Formation exposed in the Gunningbland area. This includes the first known biostratigraphic succession in Australia that extends continuously from the middle Darriwilian to the basal Sandbian. These new data are crucial for a better understanding of the geological evolution of this region in central New South Wales, and for the enhanced correlation of Ordovician rocks throughout the Macquarie Volcanic Province, which hosts substantial porphyry Cu–Au mineral deposits. [ABSTRACT FROM AUTHOR]

Late Ordovician conodont fauna from allochthonous limestones in the Wairuna Formation of the Broken River Province, north Queensland, contains 23 species typical of the deeper water Protopanderodus biofacies. Many of these species also occur in allochthonous limestones in the Malongulli Formation and correlative units of the Macquarie Volcanic Province in central New South Wales, and are also recognized in North and South China, which supports assignment of the Wairuna Formation conodont fauna to the Taoqupognathus tumidus-Protopanderodus insculptus Biozone of middle Katian age. Associated linguliformean brachiopods include species of Acrosaccus, Atansoria, Biernatia, Conotreta, Elliptoglossa, Hisingerella, Nushbiella, Paterula and Scaphelasma, which are identical to those known from the Malongulli Formation. Subtle paleoecological differences between faunas of the Malongulli Formation limestones (interpreted as forming in a deeper water peri-platform and upper slope environment) and those of the Wairuna Formation limestones imply that the latter were likely originally deposited on the shelf edge and subsequently reworked downslope. This study provides compelling paleontological evidence of strong affinity between Late Ordovician limestones of the Macquarie Volcanic Province and the Broken River Province, suggesting these regions (today separated by 1600 km) were linked by a volcanic island chain characterized by identical geochemical signatures in volcanic rocks associated with the limestones. [ABSTRACT FROM AUTHOR]

The argument that temperature change and biological change during the Ordovician are correlated and, perhaps, causally related has been advanced by measurements of δ18Ophos values on conodont apatite, a phase more resistant to diagenetic alteration than carbonates. However, the available conodont δ18Ophos records are discontinuous and are biased towards North American samples. To test the generality of global patterns and to expand the geographical range of studied regions, we document δ18Ophos values from conodont apatite as well as δ13C and δ18Ocalcite values from bulk carbonate from New South Wales, Australia. New results span most of the Ordovician and include the first Late Ordovician phosphate δ18Ophos values from the Australian continent. The data from New South Wales show an ~1. 5‰VSMOW increase in δ18Ophos values during the Early and Middle Ordovician. This pattern matches previously documented trends from Laurentia and central Australia, but values in New South Wales are consistently ~2. 5‰VSMOW lower than those from other regions. We attribute these low δ18Ophos values to local paleoceanographic effects on the seawater δ18O value. [ABSTRACT FROM AUTHOR]

Review of the traditional separation of global Ordovician conodont distribution into the North American Midcontinent Province (NAMP) and North Atlantic Province (NAP) reveals a confusing variety of concepts and definitions that hinder biogeographic analysis. Use of this twofold scheme and its subsequent variants should be­discontinued in favour of the more detailed divisions proposed here. Major biogeographical entities of the Shallow-Sea and Open-Sea Realms, separated by the shelf-slope break, are both further subdivisible into Tropical, Temperate and Cold Domains. In the Cold domains, faunal differences between the two Realms and their subdivisions are not easily discernible, since biofacies zones and different habitats were highly condensed. Faunal differences are amplified in the tropical regions, where the North American Midcontinent Province and North Atlantic Province were originally defined. Recognition of endemic taxa is essential for finer classification within domains of the Shallow-Sea Realm (SSR). Our preliminary analysis of Early Ordovician conodont distribution identifies the Laurentian Province (in the Tropical Domain), Australian­(Tropical Domain), North China (Tropical Domain), South China (Temperate Domain), Argentine Precordillera (Temperate Domain) and Balto-Scandian Province (in the Cold Domain). The Open-Sea Realm (OSR) is dominated by cosmopolitan and widespread taxa, and formal subdivision at provincial level is yet to be achieved. The North Atlantic Province encompasses both the Open-Sea Realm and the Temperate and Cold Domains of the Shallow-Sea Realm. The North American Midcontinent Province sensu stricto is more or less equivalent to the Laurentian Province, representing shallow-water regions fringing Laurentia; in a broader sense the North American Midcontinent Province includes all provinces of the Tropical Domain within the Shallow-Sea Realm. [ABSTRACT FROM AUTHOR]

The occurrence of approximately 100 rugose coral genera has been confirmed in the Devonian carbonate dominated successions of Australasia. Their temporal distribution shows that the largest faunal turnovers were in the Pragian and Givetian, with profound extinction events at or near the ends of the Emsian, Givetian and Frasnian. The evolutionary innovation and diversification of the Early Devonian rugose corals of eastern Australia are characterized by a high turnover rate in the late Lochkovian — Pragian and strong dynamism of radiation from late Pragian to medial Emsian, implying considerable dispersal to South China, central Asia and Europe. After a high intensity of origination in the Pragian, maximum diversity was reached in the Emsian. Phillipsastreids and endophyllids appeared late in the Pragian and became common in the Emsian; stringophyllids appeared in the Emsian. As elements of these families are recorded mainly from the Middle, or even Upper Devonian of other provinces of the Old World Realm, it appears that they may have originated in eastern Australia during the Early Devonian. Following a marked decrease in generic richness in the Eifelian, faunal diversity reached another high peak in the early mid-Givetian as a result of immigration of coral genera, probably from South China, central Asia, Europe and northwestern Canada in the Old World Realm. [ABSTRACT FROM AUTHOR]